Apparatus for dielectric heat seam bonding



Oct. 16, 1956 c. JUHOLA ETAL 2,766,467

APPARATUS FOR DIELECTRIC HEAT SEAM BONDING Filed June 25, 1955 2 Sheets-Sheet l I n ven tors Car! Ju/zolw Harold Cl/axfi'eld Oct. 16, 1956 c. JUHOLA ET AL APPARATUS FOR QIELECTRIC HEAT SEAM BONDING 2 Sheets-Sheet 2 Filed June 25, 1953 m 0 t n e U Tm United States Patent O APPARATUS FOR DIELECTRIC HEAT SEAM BONDING Carl Juhola and Harold C. Maxfield, Manchester, Mass, assignors to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application June 25, 1953, Serial No. 364,103

4 Claims. (Cl. 12-33:.2)

This invention relates to apparatus for making shoes. More particularly, it relates to improvements in apparatus for adhesively attaching soles to shoes in which a precemented sole and shoe are pressed together while the adhesive is activated by dielectric heat.

The use of high-frequency electric energy for the acti vation of sole-attaching adhesive has been explored extensively, and a variety of approaches involving the use of electrodes disposed adjacent to the adhesive layer to establish an alternating electric field therein have been investigated. Such use of electrodes, however, has been attended by several difficulties.

One difficulty is the convenient and proper positioning of an electrode outside of the shoe. It is diflicult to position the electrode to provide uniform heating without interfering with the action of the customary solepressur-e pad in applying uniform pressure between the outsole and shoe over the entire area of the bond, particularly where the electrode system must accommodate a wide range of sizes and styles.

Another difficulty is the provision of a desirably large safety margin between activation of the adhesive and burning of the leather. Full advantage cannot be taken of high loss-factor adhesives to secure preferential heating of the adhesive with respect to the leather without causing the electrode disposition to become excessively critical.

While some of these earlier approaches were capable of producing a satisfactory job of sole attaching under favorable circumstances, the aforesaid difiiculties have impeded the employment on a commercial scale of dielectric heat for such activation.

Accordingly, an object of the present invention is to provide dielectric heat sole attaching apparatus which will overcome the foregoing difficulties.

To this end, and in accordance with a feature of the present invention, there is provided apparatus comprising an enclosure adapted to provide a substantially closed cavity having conductive interior surfaces, the enclosure containing a sole-pressure pad and pressure applying means cooperative with said pad for pressing together a sole and a shoe, the apparatus also includes means for supplying to the space within said enclosure high-frequency electromagnetic energy while the shoe and sole are under pressure, thereby to establish an electromagnetic iield in the adhesive layer without the use of electrodes. To enhance the uniformity of heating, the enclosure is relatively large with respect to the wave length of the energy supplied thereto and is therefore capable of sustaining a. large number of modes which may be favored in turn by mode-stirring, thereby changing the field pattern periodically to provide a time integrated heating effect which may be substantially uniform throughout the layer of adhesive.

In accordance with another feature of the invention, the enclosure comprises a body portion open at its top and a cover portion, the shoe press being so disposed 2,766,467 Patented Oct. 16, 1956 that the top of the pad is above the top edge of the body portion, thus providing free access to the pad.

These and other features and advantages of the invention to be defined in the claims are described in detail in the following specification in connection with the accompanying drawings, in which:

Fig. l is a front elevation, partly broken away and partly in section of a preferred embodiment of the present invention;

Fig. la is a section taken on line 'IaIa of Fig. 1; and

Fig. 2 is a side elevation, partly broken away and partly in section, of the apparatus shown in Fig. 1.

Referring to the figures, the apparatus comprises a copper-lined steel enclosure 12 having a body portion 14 formed with a rimmed opening at the top and a cover portion 16, the enclosure 12 being supported on a member 30 (Fig. 2). The portions 14 and 16 have their mutually engaging edges formed with flanges shaped to provide a choke joint 18 (Fig. la) to reduce radiation losses, although other means for preventing escape of energy, for example, a R. gasket, could be employed. The enclosure 12 is constructed to contain a shoe press comprising pressure-applying means substantially similar to those of a single station of a shoe press of the type shown in United States Letters Patent No. 2,047,185, issued July 14, 1936, on an application of Milton H. Ballard et al.

Accordingly, secured to the member 30 and extending within the enclosure 12 is a bracket 36 (Fig. 2) on which is mounted a pad box 40 and shoe-engaging and pressureapplying devices to be described. The box 40 supports a pad 42 having pad members advantageously consisting of low-loss rubber, these members being shown in section in Fig. 1. It will be observed that the pad 40 extends above the top edge of the body portion 14, thus giving the operator free access to the pad and other pressureapplying members. On the side of the box 4i remote from the operator are two uprights 44, 46 connected at the top by a crosshead 48. The uprights 44, 46 are pivoted to the side walls of the bracket 36 below the "bottom of the pad box by a shaft 50 which extends transversely of the bracket 36. Between the uprights 4-4, 46 near their upper ends are pivoted on a shaft '52 two levers 54, 56 which extend transversely of he pad box 40. Passing through an opening formed in the lever '54 is a rod 5'8 which is guided in the crosshead 43 and in a web 59 connecting the uprights 44 and 46 for right line movement parallel to the upright 44. To the rod 58 is pinned a member 60 which extends outwardly and beneath the outer end of the lever 54 and is formed on its outer end with two cars which embrace the end of the lever 54 and are slotted to receive a pin passing loosely through them and the lever. The underside of the outer end of the lever 54 is formed with a convex surface adapted to bear on a flat surface formed on the upper side of the member 60. The member 60 is held up against the lever '54 by a compression spring 62 (Fig. 1) arranged on the rod 58 between the web 59 and the member 60. Upward movement of the front arms of each of the levers 54, '56 is limited by an adjustable stop screw 64 threaded in a lug projecting from the crosshead 48. Beneath the lever 56, a member 66 similar to the member 60 is similarly mounted on a. rod 63 and is upheld by .a compression spring 7i) (Fig. 2). The shoeengaging mechanism described is capable of swinging rearwardly about the shaft 59 from the position shown in the figures, in which the outer ends of the levers 54, 56 are disposed over the pad box, into an inclined position in which the forward ends of the levers 54, 56 are withdrawn over the pad box, thus giving the operator free access thereto. To limit this swinging movement of the uprights 44, 46, a rod 72 (Fig. 2) is pivoted to g the upright 46 by a pin 74 and passes through a swivel block 76 pivoted to the side of a fixed cylinder 78I The inner end of the rod is provided with a polystyrene washer .80 and nuts to. limitthe forward-swingingrnovement of the uprights while the. portionof. therod which passes through the swivel block. 76 is provided with a polystyrene sleeve 32, such insulationv preventing arcs between the rod 72- and they block 76- during. operation. In general, metallic joints in the. enclosure should be tight,. while ferromagnetic parts may advantageously be copper-plated to reduce energy losses.

The cylinder 78 is secured to the bracket 36 and is provided with a piston 84. beneath which is a chamber 86. into which fluid under pressure may be introduced through a pipe fie-to. move. the piston upwardly. To retract. the piston,.pins.90 at opposite sides of the piston extend through slots 92 in the opposite. sides of the cyl inder. A tension spring 94 is secured to each ofthe pins 90. and has its. lower end secured to the bracket 36. Each spring 94 is housed in a two-part telescoping cylindrical conductive housing 96 to minimizeloss ofhighfr'equency energytherein.

On the upper end of the piston 84 are secured two ears 98 between which. is mounted on a pin 100 a pressure-distrbuting device, shown 'as a"dlSt1'lblltlI1g lV6I 102, the opposite ends of which engage respectively the rear ends of the levers 5'4, 56 when the uprights 4 4, Mare in their forward positionand the piston is raised.

On the outer ends of the members 60, 56 are mounted respectively shoe-engaging devices 104, 106. The device 104 on the member '60 comprises a rubber-padded polystyrene member for engaging the forepart of the shoe. This member is mounted by means of a T-head for adjustment transversely of the shoe in the direction of thetip line in ablock :112on the lower end of a post 114 which, at its upper end, is providedwith a T-headmounted for movement longitudinally of the shoe in a T-slot formed in the lower face of the member 60. The device 106, which is adapted to engage the top of the cone of the last, comprises a contact piece 116' of polystyrene secured in a block 118 having on its upper part a T-h-ead which engages a T-slot formed in the lower side of the member 66 and extending longitudinally of the pad box 40.

To provide fluid pressure for operating the piston 84, a gear pump of usual construction (shown diagrammatically in Fig. 2) is provided, the pump being arranged by connection with an electric motor 132 to be driven constantly during the time the machine is in operation. From the delivery side 1 34 of the pump, the fluid is led by a pipe 136 to a pressure relief valve 137- which leads to a sump 138. The pipe 136 also leads to a control valve140 which is arranged to be controlled by a treadle 142 (Fig. 1), through a link 1'44 and arm 146, to connect the pipe 33 to the pipe 136 when the treadleis rocked counterclockwise (Pig. 1) and to connect the pipe 88 to a pipe 148 leading to the sump when the treadle is rocked in the other direction.

As seen in Fig. 2, the cover portion 16 of the enclosure 12 is pivotally supported on a shaft 150 secured to the frame member '30 by means of a bracket member 152 secured to the'cover portion by screws 154. The member 152 has a rearwardly extending fingerl-Sfi to which one end of a counterbalance tension spring153 is secured, the other end of the spring 158 being fastened to a bracket 166i extending firom the member 30. Secured to the bracket 160 is a solenoid 162 which is arranged when energized to pull one arm 164 of a bell crank pivoted on the bracket 160 so that the stub end of another arm 156 of the bell crank extends underneath a. lug 168 extending from the bracket member 152, thereby locking the cover portion 16 in its closed position.

Electromagnetic energy is supplied to the enclosure 12 from a magnetron oscillator 170, indicated diagrammatically in Fig. 1, through a wave guide 172 containing a matching iris 174 and a feeding tuner 176' having an adjustable stub 173. A cover 182 of polystyrene may be inserted over the wave guide at its junction with the enclosure 12 to keep particles of foreign matter out of the wave guide. 1

A pair of mode-stirrers 184, 186 secured respectively to the cover portion 16 and the. body portion- 14are-.arranged to vary the mode pattern during the time the apparatus is in operation. Each mode-stirrer comprises a pair of vanes 188 mounted on a rod 190", the. rodbeing attached at its-center to a shaft 192 pr0jecting-through the enclosure to a motor drive 194 attached to the outside of the enclosure. While the use ofonl'yo'nestirrer has been found to produce a reasonably satisfactory job, we have found that by employing two mode-stirrers arranged to rotate at right angles to each other, as illustrated, a somewhat more uniform heating pattern'may be obtained at the marginal interfaces between a shoe and sole;

The stub 178 is positioned to minimize the standing.

wave ratio for all positions. of the mode-stirrers. For. this purpose, the lower section of the wave guide 172 may be slotted to permit measurements. of said ratio;

The electric control circuits nclude a main start and.-

stop switch 200 which is arranged to control the energy supply from the line to other control circuits, the electric motor 132and' to the magnetron filament and cooling;

blower, a pilot light 202 indicating that these circuits are energized.

As indicated diagrammatically in Fig. 2, line voltage;

body portion 14 of the enclosure and has aplunger 208' which is engaged by the cover portion 16 when closed to close the contacts of the switch 204 to energize the timer 206. Leads-from-the switch contacts ofthe timer 206' areconnected to the solenoid 162,,to the motors of the two mode stirrers 184, 106'and to a high voltage power supply 209 which provides about.5',000 voltsD. .C. p

to the magnetron 170.

In operation, the operator will normallyfind the ap,

paratus with the cover portion 16 held open by the,

spring 158. Upon pressing the start button 200 the pump'motor 132is startedand the magnetronfilament.

and blower motor are also energized. The. operator may now place a shoe and sole uponthe pad 42and by depressing the left side of the treadle 142. the pressure applying devices 104 and 106 are brought to. bear upon the shoe. cemented with a suitable adhesive. While many adhe sives may be used, we have found particularly suitable those adhesives which have a high loss-factor; Such an adhesive. may comprise, for example, a solvent solution of a vinylresin and a butadiene-acrylonitrile co.- polymer rubberrwith carbon added' to improve its dielectric loss. The cover portion 16 is now closed, actuating the switch 204 to energize the timer 206 which in turn causes the solenoid 162 to lock the cover closed, starts the mode stirrers, and causes high voltage to be supplied to the magnetron which thereupon supplies'eleo trornagnetic energy to the enclosure 12; Wlien the timer has run its course, the solenoid 162is deenergized, allowing the cover portion 16 to rise. This opens the switch 204, preventingreenergization of the solenoid or magnetron until the cover is again closed; The operator may then depress the right-hand side of the treadle 1 3-2 to relieve the pressure, upon the shoeso that he may remove the shoe and replace it with another.

Having thus described our invention, what 'we claim as new and desire to secure by Letters Patent of the United Statesrisr 1. In apparatus of the class described, an enclosure adapted to provide a substantially closed" cavity having" conductive interior surfaces and adapted to be excited Previously the. shoe and sole willihave been.

with electromagnetic energy in a large number of modes, a shoe press disposed within said enclosure, said press comprising a support of adjustable contour including a dielectric pad member adapted to support an outsole and a dielectric pressure-applying member adapted to engage a shoe disposed in registering relation with a sole on said pad, means for providing relative moven ent between the pad and the pressure-applying member to press together said shoe and sole, means for supplying to the space within said enclosure electromagnetic wave energy having a wavelength small with respect to dimensions of the enclosure for elfecting radiant energy heating in a large number of modes, and means for effecting sequential changes in the mode pattern within the cavity during excitation thereof.

2. In apparatus for adhesively attaching l an enclosure adapted to provide a substan closed cavity having conductive interior surfaces, said enclosure comprising a body portion having an opening the top and a cover portion supported for movement into out of closing relation with the body portion, a pad mounted in said body portion with its upper surface above the top edge of said body portion, power-operated pressure-applying means cooperative with said pad to clamp a shoe and sole together under pressure, manually operated means arranged to control said power-operated means, and means for supplying to said enclosure electromagnetic energy having a wavelength small with respect to the dimensions of the enclosure.

3. In apparatus for adhesively attaching soles to shoes, an enclosure adapted to provide a substantially closed cavity having conductive interior surfaces, said enclosure comprising a body portion having an opening at the top and a movable cover portion, pressure-applying members disposed in said enclosure, said members including a shoe pad mounted with its surface above the top edge of the body portion and a cooperative pressure-applying member movable to clamp together a shoe and a sole, a fluid-pressure-operated motor operable to move said movable member to apply pressure between such shoe parts, a pump, an electric motor connected to said pump to drive it to supply fluid pressure, fluid connections between said pump and said fiuid-pressure-operated motor including a valve operable either to admit fluid to said motor from said pump or to discharge fluid from said fluid-oressure-operated motor, control means connected to said valve to operate it, and means for supplying to said enclosure electromagnetic energy having a wavelength small with respect to the dimensions of the enclosure.

4. In apparatus for soling shoes, an enclosure adapted to provide a substantially closed cavity having conductive interior surfaces and adapted to be excited with electromagnetic energy in a large number of modes, a first support for a lasted shoe, a second support for soling material for said shoe, said second support having a surface generally conforming under pressure to a shoe bottom, means for effecting relative movement between said supports for pressing soling material against the bottom of a shoe, means for feeding to the entire space within said enclosure electromagnetic Wave energy having a Wavelength small with respect to the dimensions of the enclosure for effecting radiant energy heating in a large number of modes, and means for effecting sequential chan es in the mode pattern within the cavity during excitation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,065 Dixon et a1. Mar. 11, 1947 2,474,977 Hart July 5, 1949 2,500,752 Hanson et a1. Mar. 14, 1950 2,564,675 Crook Aug. 21, 1951 2,595,748 Andrews M May 6, 1952 2,618,735 Hall Nov. 18, 1952 2,619,661 Hart Dec. 2, 1952 FOREIGN PATENTS 969,699 France May 31, 1950 639,144 Great Britain June 21, 1950 668,835 Great Britain Mar. 26, 1952 

